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hardened_malloc
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rely on mmap rounding to page size when possible

pull/50/head
Daniel Micay 2018-08-29 03:24:28 -04:00
parent 58d929c0f0
commit 5bc6820c24
1 changed files with 4 additions and 4 deletions
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8
malloc.c
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@ -30,8 +30,6 @@ static_assert(sizeof(void *) == 8, "64-bit only");
#define ALIGNMENT_CEILING(s, alignment) (((s) + (alignment - 1)) & ((~(alignment)) + 1)) #define ALIGNMENT_CEILING(s, alignment) (((s) + (alignment - 1)) & ((~(alignment)) + 1))
static void *allocate_pages(size_t usable_size, size_t guard_size, bool unprotect) { static void *allocate_pages(size_t usable_size, size_t guard_size, bool unprotect) {
usable_size = PAGE_CEILING(usable_size);
size_t real_size; size_t real_size;
if (unlikely(__builtin_add_overflow(usable_size, guard_size * 2, &real_size))) { if (unlikely(__builtin_add_overflow(usable_size, guard_size * 2, &real_size))) {
errno = ENOMEM; errno = ENOMEM;
@ -50,13 +48,15 @@ static void *allocate_pages(size_t usable_size, size_t guard_size, bool unprotec
} }
static void deallocate_pages(void *usable, size_t usable_size, size_t guard_size) { static void deallocate_pages(void *usable, size_t usable_size, size_t guard_size) {
usable_size = PAGE_CEILING(usable_size);
memory_unmap((char *)usable - guard_size, usable_size + guard_size * 2); memory_unmap((char *)usable - guard_size, usable_size + guard_size * 2);
} }
static void *allocate_pages_aligned(size_t usable_size, size_t alignment, size_t guard_size) { static void *allocate_pages_aligned(size_t usable_size, size_t alignment, size_t guard_size) {
usable_size = PAGE_CEILING(usable_size); usable_size = PAGE_CEILING(usable_size);
if (unlikely(!usable_size)) {
errno = ENOMEM;
return NULL;
}
size_t alloc_size; size_t alloc_size;
if (unlikely(__builtin_add_overflow(usable_size, alignment - PAGE_SIZE, &alloc_size))) { if (unlikely(__builtin_add_overflow(usable_size, alignment - PAGE_SIZE, &alloc_size))) {